The general elevation rule followed by forecasters is that for every 1,000-foot decrease in elevation, the color change occurs a week later. The university project considered published work suggesting every degree of latitude north is the same as going up by about 200 meters in elevation.

“In other words, the same elevation in the north is cooler than the same elevation in the south, which causes the vegetation to differ,” explained Dr. Howard Neufeld, whose lab focuses on physiological plant ecology. “The resultant cooler temperatures mean that peak fall colors will come earlier to those same elevations in the north than in the south.”